


Kinesthetic

by allyoops



Category: Original Work
Genre: Alpha/Omega, Ambiguously Underage, Brother/Sister Incest, Extremely Dubious Consent, F/M, First Time, Rape/Non-con Elements, dom/sub elements
Language: English
Status: Completed
Published: 2018-12-27
Updated: 2018-12-27
Packaged: 2019-09-28 14:36:47
Rating: Explicit
Warnings: Rape/Non-Con
Chapters: 1
Words: 4,385
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17184842
Author URL: https://archiveofourown.org/users/allyoops/pseuds/allyoops
Summary: Matthew hadn't planned to be his little sister's first, but when the chance to help her through a heat presents itself, he has to admit there could be some advantages to showing her how it's done.Whether or not Ashley agrees with him is a matter of secondary importance, at best.





	Kinesthetic

**Author's Note:**

> Written to the anonymous prompt: Older alpha sibling takes the virginity of their younger omega sibling. Partly out of a possessive desire to lay a claim that they were the omega's first alpha and partly out of a need to see that their first time with another alpha isn't bad.

The first time Ashley went into heat, Matthew was away at college and he missed the whole thing. When he came home there was no more evidence left of his sister's sexual maturity than the bolt newly installed on her door and a few scuffs around the front porch where a couple luckless neighbor boys had tried their luck, only to be given their dad's boot to think about on the way home.

The second time, he came home at the very end of her time and his parents made him sleep in the basement, behind another bolt, because his parents were careful like that and alphas were something you couldn't be too careful about.

The third time, though, was a fluke. Mom had all the days marked out on the calendar but she must have miscounted or Ashley maybe wasn't very regular yet, because his parents were still away on their cruise and he was alone in the house with her. They had just settled down to a very late lunch or maybe an early supper, because what were mealtimes when your parents were away, really, when he suddenly caught a whiff of something ungodly sweet and spicy in the air around his sister.

“Ashley?” he said, but it came out rough and gravelly, not like his usual voice. She looked up at him in confusion and then, belatedly, awakening shock.

“Oh no,” she said, but she sounded uncertain.

Like she was waiting for him to decide what to do.

Put some distance between them, right? Lock her in her room, shut himself in the basement, call Aunt Kathy or the public health nurse or whoever you called to come deal with this kind of thing. Not him. He couldn't be trusted to be in charge.

But he was still her big brother, and not even her heat was going to change that. She was looking up at him with perfect, patient trust, waiting for his guidance, and the damnable submissiveness of that very act was what did him in.

“Get upstairs,” he said hoarsely, and she did as he ordered, entering her bedroom and sitting meekly on the bed while he slammed the door shut and threw home the lock.

He stood on the other side, forehead pressed against the timbers, breathing hard, thoughts racing.

His sister. Ashley. She was his sister. He should not be thinking the thoughts he was thinking now, not about her, not about his sister, not even now with the thickening perfume of her availability filling the room beyond the door, advertising her to every interested alpha within range of the wind pattern.

Advertising her to _him_.

He stumbled downstairs and slept in the basement that night, but when he woke in the morning the whole house had changed. It was thick with the smell of her; the _need_. His cock had woken before he did and when he opened his eyes it was erect and ready before him, a rigid arrow in the prison of his boxers, pointing a very determined path upward to where the source of his torment slept sweetly behind the safety of her bolted door.

Like she was a hidden treasure, kept safe and ready.

All for him.

He tried to banish the resurgence of thoughts, but this morning he lacked the willpower. Sleep-stupid, already well into his responsive rut, he could not cope with the social strictures that should have kept him from seeing Ashley as he thought of her now. Instead he knew only that she was waiting, ready, and if he played this thing right, she would not even refuse him.

He had just enough presence of mind to shower, first. He wasn't an animal, after all, and Ashley's first time—he fumbled the soap, just forming that thought—should be with somebody who tried to make it good for her.

So he forced himself to take the time to clean up, to make himself a little presentable, before he climbed the stairs to her room and hovered just outside her door, breathing deeply.

Even through the door, the ripeness of her was intoxicating. More than any omega he'd ever smelled before. She was sweet and ready, even though she could hardly even know what it meant _to_ be ready. His hand trembled as he laid it on the bolt, drew it back, and opened the door.

She was already awake and out of bed, although she was still in her nightshirt, hair tousled from what little sleep she'd managed to steal before the fullness of her heat set in. She looked up from where she sat at the cluttered little desk that served as her vanity, surprised by his entry.

“Matt,” she said, “you shouldn't—”

Then she broke off, her eyes dropping from his to the sight of his erection straining painfully against the clean boxers he'd thrown on before mounting the stairs. He could see every emotion flash across her face in real time, as intimate and clear as if she'd explained them to him herself.

Surprise, first. Genuine shock, at the sight of him ready to fuck. Like the idea of her big brother being somebody who ever could be ready to fuck had never crossed her mind. But now that it had, surprise was chased by uncertainty.

He felt a rush of protective concern, seeing her unsure. It wasn't quite fear, but it was hesitation, and he was not yet past the stage where her reluctance would check his demands of her. If she needed him to hold back, to be gentle, patient, he could still try to manage that . . . but then the uncertainty he saw in her face shrank, reduced, and became secondary to her instinct.

It was not exactly lust, what followed, but it was acceptance. He read it plain as day even from across the room. She dropped her head just a little, comprehending, accepting . . . submitting.

She would take him as her first.

A surge of animal dominance unlike anything he had ever felt before roared through Matthew's bloodstream at the sight of his little sister surrendering to the mere sight of his desire to fuck her. His hands shook with the agony of self-control as he closed the door behind him, moved across the floor and waited for her to come to him.

She moved timidly, and he liked it. Some omegas were needy and demanding in their presentation, heat-crazed and ready to fall on any knot, but not his sister. Ashley's shyness appealed to him. Made him feel the master of the situation, and desire to stay that way. So when she came to a halt in front of him, eyes still fixed on the bulge in his boxers, he knew what he wanted her to do.

“Take it out.”

She dropped to her knees and obeyed. Her willingness made her clumsiness all the sweeter as she awkwardly tugging the waistband of his boxers down over his cock. When it sprang up in front of her again, naked and ready, she stared in almost comical surprise. He groaned deep in his throat, glorying in her reaction, feeling the need for her pulsing all through him to fever strength.

“Lift your shirt up.”

She did, baring her belly, breasts and the softly-furred flat of her pussy to his view all in one simple, unerotic motion. Her shirt, raised, hid her face and made a display of her body for his enjoyment.

Her breasts were puffy and plump, nipples stiff and erect from the heat. From the vee of her thighs emanated the rich, warm scents of paradise, and he unblushingly knelt to press his nose to the crisp curls, breathing her in deeply with undisguised hunger.

“I'm going to fuck you, Ashley.”

She trembled. He couldn't see her face, and he needed to. Needed, suddenly, to know the full extent of her reaction to the inevitable, and not just the effect it had on her pussy, which was definitely strongly in his favor. So he stood, lifted her shirt over her head, and looked down into her face.

Her cheeks were pink, her eyes bright. She worried at her bottom lip, and he smiled.

“Are you scared?”

She hesitated.

He growled softly, like the delay was too much to tolerate, so she rushed to answer.

“No. I— maybe?” She looked down at her own naked body, and his, as if imagining what was to come; as if wondering how the two could ever be joined. “I don't know what to do.”

Of course she didn’t. That her body would eventually help her through it did not change that she had no understanding of what was to come, of what it would mean for her. Of course she’d be nervous.

“That's fine,” he said. “You don't have to. Most of it is biological anyway. You'll want it by the time I'm done, even if you don't want it now.”

That promise seemed to comfort her. She nodded, accepting that he must be telling the truth, because why would he ever lie about this?

“Will you—would you stop, if I asked?”

He considered lying to her now, but didn't see the point.

“No.”

Strangely enough, even this seemed to bring comfort. She smiled timidly.

“I . . . don’t laugh, Matty, but I like the way I feel, when you say that.” She put her hand between her legs to show where exactly the good feeling came from, innocently wondering at the mystery of her own body. “Why?”

“Because that's where I belong,” he said simply. “In your cunt. You feel that?” He placed her free hand on the thickness of his cock, letting her know what was about to happen, the magnitude of what she was in for.

“This belongs inside you, Ash. That's what your body's telling you right now. When you say you don't want it, or ask me to stop, I'll have to ignore you and keep going anyway. Your body knows that.”

Her flush deepened, and he could tell the words themselves were having a strong effect on her. The promise of her helplessness gave her pleasure, even if she didn’t fully grasp why. He continued the explanation, gentle, patient.

“Your cunt needs me inside it, and that's the only thing that really matters. You'll get better at it all with practice, Ashley, I promise. It won't feel so strange after a while. But for now when it's new, it's okay if only part of you wants it. The rest of you will still feel good, and let you know that what's happening is all right. I promise.”

She smiled bravely up at him, eyes shining with nervous tears.

“I—I don't think I _like_ this very much.”

“It's okay,” he said gently. “You don't have to, right now. You just have to learn to take it.”

Her tears spilled, then, but she nodded her acceptance.

She kept crying softly even as she spread her legs at his command, offering him access to explore, finger, test the sweet and ready slick of her virgin cunt. She kept her face averted as he checked her readiness, but when he told her to look at him she obeyed without hesitation. She let him kiss her mouth, her breasts; whimpered only a little when he nibbled on the sweet pink tips. And when he knelt again to smell her, he heard her sigh softly in pleasure, and rewarded her pussy with a gentle kiss.

Then he knew he could wait no longer; knew that further waiting would only stress her unduly, when what she needed most was to be shown that taking a cock was not something to fear, as long as the person forcing you to take it had your best interests at heart. He would force his cock inside her, and she would settle around it, just as she was supposed to do.

And then, Matthew thought, looking down at her with a surge of rightness and pride, he'd be her first. The one she'd measure any and all future alphas against. Her brother's cock would always be the gold standard by which she judged a man, and Matthew liked it that way.

“Get onto the bed, Ashley.”

She moved to obey, but since she did not understand what was required she laid on her back instead of assuming the correct position, looking like a bride on her wedding night, splayed and pliant, staring at him with quiet, unresisting surrender. It was so placid a position, so vulnerable, that he decided to let her have it that way for a while. He could give it to her gently, stage by stage, until she was in the right frame of mind to take her first proper fucking from an alpha.

So he climbed on top of her without issuing any correction, positioning himself over her just as she was, belly up, breasts and pussy offered for his use. He drank in the sight, relishing it, savoring the knowledge that no man had beheld her like this; that no man ever would. She was untouched, ready to be taken, and he was the one to take her.

“Here, Ashley,” he murmured, putting the tip of his cockhead to the swollen entrance of her heat-slicked cunt, “it will be all right after this.”

And bearing down, he gave his baby sister her first cock.

He was gentler than he ever would have imagined possible, given the advanced stage of her heat and his rut. He was iron-hard and she was nothing but sweetness beneath him, barely crying out at all as he split her cunt for the first time. Her breasts quivered bewitchingly with each sobbing breath, inviting him to feast. He tasted each, savoring her, then kissed her mouth deeply, loverlike, while he rocked relentlessly forward.

She wanted him. She was scared of him. She did not understand how she could both hate and want one act at the same time, and she wanted to beg him to stop. He could hear all of the conflict boiling up in her with each wet breath, each ragged gasp, as she took him in and fought the opposing forces of need and fear. Her heat was not yet master of her inexperience, and it was his job to teach her the necessity of surrender to her cycle.

If he could fuck her as far into a state of pleasure as possible, her submission would be all the easier to secure. Omegas were so dependent on their own pleasure, and truth be told Matthew was starting to feel a little dependent on her pleasure, too. If he could get her to come on his cock, to take pleasure from him readily, even eagerly, then the pain he would also need to inflict would be accepted in more the proper frame of mind as well.

So he set to giving her what he could, his mouth on her breasts, his thumb teasing the soft, plump flesh around the prize of her clit as he fucked gently into her. She still whimpered under him, but the fear that knotted her muscles was starting to ease, and between her weepy little cries now and then came something richer, sweeter, and closer to a moan. Emboldened, he increased his attention to her clit and was rewarded with a sharp gasp.

She didn't come, not yet, but he could see in her face the exact moment she started to want to. And that was all he needed.

“I'm going to give you an orgasm, Ashley,” he said softly. “You’ll like it, I promise. It will help you get ready for what needs to happen next. This is maybe going to get a little scary, but it will make you feel good, and you're going to be a good girl for me, okay? You're going to take it all just fine.”

Before the ominous words could fully penetrate, he was already working on her clit, pressing his fingers where he felt the swelling rise up to meet them, diddling her with a remorseless efficiency that his own rut demanded of him. Ashley was still scared, but her arousal was as demanding and relentless as the brother whose cock filled her. Almost against her will, her hips rose up to seek the pressure. Unthinking, she ground against his hand, sobbing, breathless, needing the release his rhythm promised. Her cunt juiced greedily in anticipation of what was about to take hold of it, and Matthew prepared himself for what had to follow.

Even so, when his baby sister came on his cock, Matthew nearly lost control. She was the most amazing thing he'd ever seen, eyes and mouth opened wide, tears spilling down her face, mewling little screams spilling from her throat like music notes. Her cunt clamped and pulsed around him like a living thing; like it had always known this was where it belonged. She went rigid, transported, beneath him, and for just a moment Matthew let himself drink in the sight.

Then, as she softened, collapsing, every limb gone limp and useless, he moved.

He lifted her right leg straight in the air, crossed it in front of him and got her on her side just like he was assembling furniture. With his dick still buried inside her, he hoisted her up, ass in the air, face down in the pillows, and made her ready to be fucked.

 _Really_ fucked.

Like an alpha must always fuck an omega, to make the final connection.

The knot Ashley did not know enough to understand she craved would need to be buried inside her before they were done, and there was no way Matthew knew of to knot an omega that did not come from a hard, brutal fuck.

So he got her into position, his limp, post-orgasmic, beautifully trusting baby sister. He made sure his weight was spread out over her back, his arms on either side of her head, the nape of her neck vulnerable to the likely necessity of speedy punishment from his teeth if she should try to escape before she had taken her due . . . and he fucked Ashley.

As she was always meant to be fucked.

And Ashley, despite her obvious pain, despite her confusion and fear and, yes, twice, her frantic, futile effort to crawl out from beneath him only to find herself pinned in place by his teeth on the back of her neck, took it all.

He pounded into her and she begged him to stop, as he had known she would. She cried, as he had expected, but he felt they were mostly the tears of a girl overwhelmed beyond her capacity, senses battered by the desires of her alpha, all while instinctively aware that the only way out of this was to weather it bravely and take what he demanded she accept.

Her biological submission came much sooner than Matthew had imagined it would. Even as his knot was only beginning to swell, he felt her surrender spread through her. Her head drooped on the pillows, the renewed tension eased from her limbs, and finally, most significantly, she arched her back downward, driving her hips back up against him to offer a more complete acceptance of his cock to her cunt.

Matthew felt the molten fire of victory, of conquest, roll through him. He hammered home brutally in response, testing her, and she, his perfect sister, imprisoned by the cock in her cunt, simply closed her eyes and took it.

She was perfect, in every possible way, and Matthew was nearly sobbing himself by the time his knot approached full size and he made his final, brutal demand of her: of her cunt. The stretch and strain must have been agony. He could not imagine they would be otherwise. He’d heard omegas describe their first knotting with lingering horror and desire in equal measure; the impossible demand it placed on them, coupled with the impossibility it was to refuse. He imagined what that must be doing to his little sister as he forced it into her, the overwhelming duality of fear and desire that her brother was forcing her to take, and he nearly came at the very thought.

He thought he heard her groan, as he ensured her acceptance of him; a low, animal guttural, part fear, part satisfaction. But then she parted to let him in, his knot drove home and she took him all, and he was past caring what she felt.

His knot continued to swell inside her and he thrust madly to the very depths of her cunt, battering heedlessly, conquering, claiming all he held between the prison of his braced arms as his exclusive conquest. And she, still presented to him in the most perfect way imaginable, took him all, gave him all, so that he knew beyond any doubt she perfectly understood her place.

“You're such a good girl, Ashley,” he crooned, bearing his weight down cruelly on her, relishing her willingness to support him without complaint. “Oh, fuck, Ashley, look at you baby, you're taking it so fucking good.”

How could he have doubted her? His perfect baby sister. Her heat surrounded him now, his cock at home, her cunt his proud domain. He would flood her with his semen and she would never know another man for her first. It was so good. So perfect. So right.

Before he came, he regained control of himself just enough to draw back and stare down at where they were joined. The perfection of it was almost unbearable. His knot sealed her cunt perfectly, the poor abused lips stretched obscenely around the size of him, her captivity on his flesh secured. He could fill her at his leisure and be assured of her acceptance of everything he gave her.

Still she lay there, posture perfect, unresisting. Her head was pillowed on her arms now, and the deep serenity of her acceptance was marred only by the tracks her tears had made on her face.

He leaned forward, enjoyed the little sounds she made at the sensation of him moving within her, and kissed them all away.

Then he held her hips in place, gave her such a final remorseless hammering that he doubted she would be able to sit and fail to feel the reminder of his presence within her for a week or more, and came.

He shouted some vague obscenity as he did, clutching her hair, then fell on top of her back and bore her down onto the bed. She collapsed, and did not complain once in the several minutes it took him to come to his senses.

He tested the strength of the knot, and it held. At that he could finally ease up, into a sitting position. She sobbed just once at the tug on her cunt, the knot dragging her limp body backward with him until he pulled her back along with him, easing the tension of their knotting and settling her naked, sweaty body onto his lap.

“There, now,” he soothed, pushing her hair back from her face and smiling up at her. “That wasn’t so bad, was it?”

She smiled weakly, hiccupped, then looked away. He smiled.

“You took that like a champ, Ashley. I'm so proud of you.”

He took her chin in his hand, understanding that she could not choose it on her own yet, and forced her to look back at him.

“Your first time, huh, sis? And with your big brother. You did a real good job. Bet you didn't know you had it in you, huh?”

She shook her head, eyes dropping. The mid-knotting deference was still very strong, and she wouldn't challenge him with eye contact if she could possibly help it until after they had separated.

“Well, you did great.” He pressed a gentle kiss to the tip of each breast, and a shivery sigh went out of her. He smiled.

“You like that?”

He tongued them softly, knowing they would be exceptionally tender for some time yet. He enjoyed the lusty abandon of her response, all gusty sighs and whimpers. Feeling her twist and turn on the knot that still trapped her, he understood what she was trying to do even if she herself did not. Inspired, he fit his fingers to either side of her clit and rubbed her there, watching her eyes widen, her breath come faster, then faster still, until she came again right on his knot, shaking with a helpless cry, clamping around him so gorgeously he'd have come again too, if he'd had it in him.

She drooped against his shoulder when she finished and he nipped her neck in rough approval.

“God, Ash, you're so fucking perfect.”

“You really think so?” she asked shyly, barely audible. “Even when— when I wasn't sure I wanted it?”

The sweetness of her was almost unbearable. Her desire to have been pleasing to him, her anxiety over a perfectly natural, virginal reluctance, and the searing, juicy heat of her still warming his knot and cock . . . she was perfection. He stroked her hair and smiled.

“I didn't mind that. Gives me something to overcome, you know? Conquer. Alphas like to know they're in control, but it feels even better if we have to fight for it. You made it real good for me, Ashley, I promise. Tears and all.”

She smiled proudly now, through a veil of fresh tears. These were pure gratitude, and he kissed them each away as they fell.

“I'm so glad, Matty. I wanted to be good for you.”

“You were, honey. You really were.”

He leaned in to kiss her again, surprising them both when his knot popped free. He smiled warmly at her, eased her down on the bed and took in the sight of her cunt: well used, more than a little abused, and the most perfect thing he'd seen in all his life.

She sighed and settled deeper into the covers, her exhaustion overtaking her at last.

“That's my girl,” he whispered, stroking her hair, watching her drift off to sleep. “Get your rest.”

He planted a soft kiss on her shoulder, then chased it with a preparatory nip.

“You're going to need it.”


End file.
